Abstract: The present invention provides a gas delivery device and system and methods for delivering humidified pressurized gas through a conduit to a subject. The configuration of the elements of the gas delivery device enable the device to be conveniently oriented from a horizontal to vertical position to suit the needs of a user. The gas delivery device may incorporate a Helmholtz resonator for dampening sound of the motor. The conduit may incorporate concentric tubes to allow it to conveniently engage the humidifier at a single aperture. The invention includes a method of operating a blower motor for a gas delivery device using a single Hall sensor.

Abstract: The present invention provides an integrated electrode connector and impedance indicator apparatus comprising of an electrode connector, an impedance indicator means; and a light-transmitting housing. The impedance indicator may be located in a recess in the housing. Preferably the impedance indicator means is an LED. Preferably the impedance indicator emits light when the impedance is outside of an operational range. The apparatus is suited for applications such as indicating the status of EEG electrodes.

Abstract: In one embodiment, the present invention includes a test signal generator capable of producing an impedance test signal comprising of a sine wave having a known frequency. The test signal generator may include a crystal oscillator, a counter, and a lookup table. The lookup table output is applied to a digital to analog converter and is then low pass filtered using a conventional analog filter to produce a sine wave of a known frequency and voltage amplitude. The test signal flows through the electrode and combines with an electrophysiological signal to form a combined signal. A signal processor is used to isolate the combined signal into the test signal component and the electrophysiological component. The signal processor digitally low pass filters the combined signal and the output of the low pass filter is the electrophysiological signal. The signal processor then digitally bandpass filters the combined signal using a filter with a center frequency which is the same as the test frequency.

Abstract: The present invention provides a gas delivery device and system and methods for delivering humidified pressurised gas through a conduit to a subject. The configuration of the elements of the gas delivery device enable the device to be conveniently oriented from a horizontal to vertical position to suit the needs of a user. The gas delivery device may incorporate a Helmholtz resonator for dampening sound of the motor. The conduit may incorporate concentric tubes to allow it to conveniently engage the humidifier at a single aperture. The invention includes a method of operating a blower motor for a gas delivery device using a single Hall sensor.

Abstract: The invention provides a nasal cushion for a mask assembly for delivering pressurised gas to the nose of a subject for treatment with continuous positive air pressure. The nasal cushion includes a self-supporting side wall defining a nose-receiving cavity; the side wall extending from a first end to a second end. The side wall is formed continuously with a thin membrane extending inwardly from a second end of the side wall into the nose-receiving cavity for sealingly engaging the nose, upper lip and cheeks of a subject. The side wall has continuously varying thickness. The first end of the side wall is adapted to engage a mask frame. The invention further provides a mask assembly for delivering pressurised gas to a patient, the assembly including a nasal cushion for sealing against the nose, cheek and-lip area the nasal cushion as described, a frame for receiving the nasal cushion, and a headgear, the headgear including a rigid arm for positioning behind the ear of a patient.

Abstract: The subject invention overcomes the problem of electrical interference in signals taken during an MRI procedure by using a long cable and a unity gain buffer amplifier near the patient, with a low output impedance to drive the cable and thus greatly reduce the capacitively coupled interference. Passive low pass filtering is incorporated prior to the buffer amplifier to attenuate high frequency interference from the MRI system. Since the buffer amplifier requires no digital signals and does not emit high frequency signals, it does not interfere with the MRI system.

Abstract: In one embodiment, the present invention includes a test signal generator capable of producing an impedance test signal comprising of a sine wave having a known frequency. The test signal generator may include a crystal oscillator, a counter, and a lookup table. The lookup table output is applied to a digital to analog converter and is then low pass filtered using a conventional analog filter to produce a sine wave of a known frequency and voltage amplitude. The test signal flows through the electrode and combines with an electrophysiological signal to form a combined signal. A signal processor is used to isolate the combined signal into the test signal component and the electrophysiological component. The signal processor digitally low pass filters the combined signal and the output of the low pass filter is the electrophysiological signal. The signal processor then digitally bandpass filters the combined signal using a filter with a center frequency which is the same as the test frequency.